10 



SCIENCE. 



[N. S. Vol. XXIV. No. 601. 



success of preventive medicine, will bring 

 about deterioration of the race. I believe 

 the argument to be fallacious, and that we 

 already have sufficient experience to show 

 that there need be no serious apprehension 

 of such a result. 



Before some accurate knowledge of the 

 causation of infectious diseases was se- 

 cured, preventive medicine was a blunder- 

 ing science, not, however, without its one 

 great victory of vaccination against small- 

 pox, whereby one of the greatest scourges 

 of mankind can be controlled and could be 

 eradicated, if the measure were universally 

 and efficiently applied. The establishment 

 upon a firm foundation of the germ doc- 

 trine of infectious diseases, the discovery 

 of the parasitic organisms of many of 

 these diseases, the determination by experi- 

 ment of the mode of spread of certain 

 others, and the experimental studies of in- 

 fection and immunity, have transformed 

 the face of modern medicine. The recogni- 

 tion, the forecasting, the comprehension of 

 the symptoms and lesions, the treatment 

 of a large number of infectious diseases, 

 have all been illuminated and furthered, 

 but the boon of supreme import to the 

 human race has been the lesson that these 

 diseases are preventable. 



Typhus fever, once wide-spread, and of 

 all diseases the most dependent upon filth 

 and overcrowding, has fled to obscure, un- 

 sanitary corners of the world before the 

 face of modern sanitation. 



In consequence of the knowledge gained 

 by Robert Koch and his coworkers, Asiatic 

 cholera, to the modern world the great rep- 

 resentative of a devastating epidemic, will 

 never again pursue its periodical, pandemic 

 journey around the world, even should it 

 make a start. 



Of bubonic plague, the most dreaded of 

 all pestilences, which disappeared mysteri- 

 ously from the civilized world over two 

 centuries ago, we know the germ and the 



manner of propagation, and, although it 

 has ravaged India for the last ten years 

 with appalling severity, it can be and has 

 been arrested in its spread when suitable 

 measures of prevention are promptly ap- 

 plied. 



Typhoid fever, the most important in- 

 dex of the general sanitary conditions of 

 towns and cities, has been made practically 

 to disappear from a number of cities where 

 it formerly prevailed. That this disease 

 is still so prevalent in many rural and 

 urban districts of this country, is due to 

 a disgraceful neglect of well-known meas- 

 ures of sanitation. 



To Major Walter Reed and his colleagues 

 of the army commission, this country and 

 our neighbors to the south owe an inesti- 

 mable debt of gratitude for the discovery of 

 the mode of conveyance of yellow fever by 

 a species of mosquito. On the basis of 

 this knowledge, the disease, which has been 

 long such a menace to lives and commercial 

 interests in our southern states, has been 

 eradicated from Cuba, and can be con- 

 trolled elsewhere. 



Another army surgeon. Major Ross, act- 

 ing upon the suggestion of Sir Patrick 

 Man son, had previously demonstrated a 

 similar mode of incubation and transporta- 

 tion of the parasite of malaria, discovered 

 by Laveran, and it is now possible to at- 

 tack intelligently and in many localities, 

 as has already been proven, with good 

 promise of success, the serious problem of 

 checking or even eradicating a disease 

 which renders many parts of the world al- 

 most uninhabitable by the Caucasian race 

 and, even where less severe, hinders, as does 

 no other disease, intellectual and industrial 

 activities of the inhabitants. It is gratify- 

 ing that one of our countrymen and a mem- 

 ber of the board of directors of this insti- 

 tute. Dr. Theobald Smith, by his investiga- 

 tions of Texas cattle fever, led the way in 



